Method of coloring stone



memes Jan. 19 1931 UNITED S ATES PATE T OFF-ICE". I

swam December is. use, Serial no. sues '5 Claims. (c1. 41-) This invention relates to the process of coloring marble, limestone, cement and other absorbent, naturalor manufactured building or monumental material containing calcium. and hereafter designated as stone, and particularly to a process whereby the coloring of the material is produced to a sufiicient depth in the stone-t0 insure a lasting coloring and to a definitely determined area.

The present methods of coloring designa portions of marble or other calcareous stones is by the application of a coloring material to the 7 surface thereof, which at best is of relatively short duration. A v permanent stain or :dye

1. that might be applied to,the stone that would penetrate the desired depth to cause a permanent coloring would. because of capillary attraction, also color the surface of the stone adjacent the design to be colored, thus causing a ragged 9 effect which would be very objectionable.

The present invention overcomes the above objections and produces a clean cut outline of the designs colored and at the same time gives a depth of coloring that will insure a colored de- 25 sign even though the stone is eroded to a marked degree.

One of the principal obiects of the present invention is the process of coloring marble, etc., which includes hermetically sealing the surface of the marble adiacent the designs to be colored,

then applying a fluid coloring matter to the design and permitting it to penetrate the stone to produce a sharp outlined design that will remain so as long as the stone is not worn away below 35 the depth of penetration of the coloring matter. In order to produce the proper coloring of the stone, it has been found desirable to use an inorganic chemical that reacts with the stone-to form a permanent color within the. body thereof 40 and alsowtends to harden .the surface of the stone, thereby making it substantially impervious to the natural weathering elements and preserving the stone for a longer periodof-time. The reactive solutions best suited for coloring 45 the stone consist of sluice-fluorides of various metals such as ir n, chromium, copper, cobalt, etc., which react with the different forms of cal- 'ciumofthestonetoformpermanentoxldesor.

More definitely, the coloring solution consists of a soluble filtrate resulting from the complete interaction of hydroiluosilicie acid. water and various metallic oxides. hydroaides, carbonates,

crothsrsuitablesalts.

The exact properties of the solution, such as its penetrabllity, intensity of color, etc., depend to a marked degree upon the proportions of the ingredients, order and amount when combining, completeness of neutralization, whether heated g andfto what degree. etc. These solutions react with the calcium carbonate of the stone. It is thoughtthat this reaction gives calcium fiuosilicate and the colored insoluble oxides and/or carbonates of the particular metal in dispersed 1g form.

' It is one of the chief values 61 this method of coloring the stone that a coloring solution is used that will penetrate the stone and produce therein a permanent color. However, the use of this penetrating material without proper coni'inement to the predetermined areas would be impracticable because of its tendency to creep or spread to those portions of the stone adiacent the design to be c lored, thereby preventing a definite demarkati n of the design.

In order to overcome this creeping of the coloring solution. I have conceived the Mean! sealing all portions of the stone adjacent the the fluosilicates into the surface of the stone about the design. I

"Dope, the name given to gelatin compound commonly used in the stone industry for masking. etc., has been found to be suitable for use inv sealing the surface of the stone. o

This methodis applicable for use where the designs are incised, reliefed or carved, or combinations, the only requisite being that the surface of the stone forming the design be so treated as to open the pores sufficiently to perg mit proper penetration of the coloring liquid. Band blasting hasbeen found most satisfactory due to the fact that it thoroughly opens the pores of the stone.

Reference will now be had to the accompanys ing drawing. wherein:

Figure l is an elevational view of a stone having a design formed thereon in accordance with this invention, and

Fig. 2 is a sectional view taken on line Iii-II so with a liquid gelatin it. This cor-Ii ering is permitted to congeal to a solid state to form a mask over said surface, thereby hermetically sealing the same.

The desired designs It to be colored are cut from the mask, thus exposing the surface of, the stone. The exposed surface of the stone is then cutaway as at l6 to the desired depth by a sand blast. After the sand blasting is completed and the remaining portions of the mask still in position, the stone is positioned with the decorated surface in a horizontal position, a fiuosilicate of metal solution is deposited on the sand blasted designs and permitted to penetrate 'the stone to the desired depth. After the reaction set up in the stone is completed and the surface of the stone is freed from the coloring solution by washing or otherwise, the remaining masking material is removed in the usual manner and the entire surface washed.

It will be found that the coloring solution has not entered the stone surface adjacent the design and that there are no coloring stains adjacent the predetermined colored areas. A definite and distinct line of demarkation between the masked portions and the design will be obtained, and the coloring will extend into the stone at substantially perpendicular relation to the surface of the stone. Some stones colored by this process have been colored to a depth of more than one-fourth inch.

It is thought that when the fiuosilicate of iron, or of other metals, impregnates the stone. that the carbon dioxide of the calcareous stone is released and replaced by fiuosilic acid and that the salts formed by this reaction are insoluble, producing the desired coloring of the stone to great depth. Not only is the stone colored, but the-process also produces a hard layer i8 over the entire design surface which makes it more impervious to destructive elements.

Many other, mask materials might be used; furthermore, the design might be otherwise engraved or produced in relief without material changes in the method.

As stated above, fiuosilicates of different minerals might be used to obtain the desired colorings, also, it has been found that combina tions of these coloring solutions may be used to obtain effects not otherwise obtainable.

It is important to not: that the sealing or masking material must be of such nature that it will completely close thesurface pores of stone to prevent creeping of the coloring solution. It has been found that the ordinary rubber stencil or "jiify gelatin stencils when used in this method will not close the pores and consequently will not prevent creeping.

In certain instances it is impractical to position the stone horizontally during the coloring process. This is true where the stones are in position in building structures, etc. In such cases,. the liquid coloring material is deposited on the design by means of a brush or similar instrument, and it will be found desirable to make more than one application of the coloring solution in order to obtain the proper depth of penetration. When the different coats are applied, it has been found best to permit each coat to dry before applying the next coat.

Many minor changes mightbe made in the different steps of this method without departing from the spirit of the invention.

What we cla m is:

1. A process of coloring calcareous stone which consists in hermetically sealing the surface portion of the stone about restricted areas to be colored; cutting away the surface of said restricted areas; and applying iiuosilicate of metal to said restricted areas whereby the stone therebeneath is impregnated.

2. A process of coloring calcareous stone, which consists in hermetically sealing that portion of the stone adjacent its surface; cutting designs in said sealed surface; and applying fluosilicate of metal to said out design whereby the stone therebeneath is impregnated and colored.

3. The method of coloring calcareous stone, comprising coating the surface of the stone with a layer of liquid gelatin and permitting it to penetrate into the pores of the stone and congeal to a solid state to hermetically seal said surface; removing a portion of said layer of gelatin to expose a portion of the surface of the stone corresponding to the desired design; cutting into said exposed surface of the stone to the desired depth; and applying fiuosilicate to the exposed cut surface of the stone.

4. The method of coloring calcareous solids, consisting in coating a portion of the surface of said solid with a material to fill the surface pores and to form an air-tight mask thereover; cutting a design from said mask, thereby exposing the surface of the solid corresponding to said design; sand blasting said design to cut away said solid to a desired depth; and applying a fluosilicate of metal to said etched design to impregnate the solid beneath said design.

5. The method of coloring calcareous stone consisting in coating a surface with a material to fill the surface pores and produce a hermetical mask thereover; cutting a design from said mask to expose the surface of said stone; sand blasting said design to cut away said stone to a desired depth; applying fluosilicate of a metal to said design to impregnate the stone therebeneath; and removing the remaining masking material from said surface.

CLARENCE E. CLEVELAND. VINCENT E. PETERSON. 

